The mood in here

Browser closing and reopening glitch

I'm having a problem on both of my computers with this version of Firefox. After using it for browsing and closing the browser, I'm unable to get the browser to reopen. I get a message that says that the program is already open, to close it and try again. However, there is no open window/browser that is visible. When I go to the task manager, I can find Firefox running in the processes tab and then I can shut that down & I can get the browser to then reopen.